package com.tang.config;

import com.alibaba.fastjson.JSONObject;
import com.tang.system.vo.Result;
import com.tang.utils.CommonUtils;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.http.HttpStatus;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

@Slf4j
public class JwtFilter extends BasicHttpAuthenticationFilter {
    private static final String tokenName = "x-access-token";

    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        try {
            executeLogin(request, response);
        } catch (RedirectLoginException redirectLoginException) {
            throw redirectLoginException;
        } catch (Exception e) {
            errorResponse(e, response);
            return false;
        }
        return true;
    }

    private void errorResponse(Exception e, ServletResponse response) {
        if (e instanceof RedirectLoginException) {
            response.setContentType("application/json");
            Result<Object> result = Result.error(e.getMessage());
            result.setCode(501);
            writeResult(result, response);
            return;
        }

        Result<Object> result = Result.error(e.getMessage());
        result.setCode(500);
        writeResult(result, response);
    }

    private void writeResult(Result result, ServletResponse response) {
        try {
            response.getOutputStream().write(JSONObject.toJSONString(result).getBytes(StandardCharsets.UTF_8));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String token = httpServletRequest.getHeader(tokenName);
        if (StringUtils.isEmpty(token)) token = httpServletRequest.getParameter(tokenName);

        if (CommonUtils.isEmpty(token)) {
            throw new RedirectLoginException("您还没有登录, 请登录");
        }

        JwtToken jwtToken = new JwtToken(token);
        getSubject(request, response).login(jwtToken);
        return true;
    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }
}
